U.S. patent number 8,204,420 [Application Number 12/200,156] was granted by the patent office on 2012-06-19 for fuser with end caps having protuberances for reducing belt skew.
This patent grant is currently assigned to Lexmark International, Inc.. Invention is credited to Patrick Wayne Carr, Jr., Gregory Daniel Creteau, Larry Steven Foster, Hnshikesh Pramod Gogate, David Erwin Rannick.
United States Patent |
8,204,420 |
Carr, Jr. , et al. |
June 19, 2012 |
Fuser with end caps having protuberances for reducing belt skew
Abstract
A fuser has a heater housing extending through an endless belt
with end caps on the housing adjacent to opposite lateral sides of
the belt. The end caps have inner flanges spaced radially outward
from a center portion and radially inward from the opposite
marginal side edge portions of the belt so as to define clearance
therebetween. Protuberances on the inner flanges of the end caps
project toward opposite marginal edge portions of the belt and are
circumferentially spaced apart to reduce belt skew relative to the
end caps by either decreasing the surface area of contact of the
inner flanges with the opposite marginal side edge portions of the
belt to reduced surface areas of contact of protuberances therewith
or decreasing the radial height of the clearance between the inner
flanges and opposite side edge portions of the belt to the reduced
radial height between the latter and the protuberances.
Inventors: |
Carr, Jr.; Patrick Wayne
(Corinth, KY), Creteau; Gregory Daniel (Winchester, KY),
Gogate; Hnshikesh Pramod (Lexington, KY), Foster; Larry
Steven (Lexington, KY), Rannick; David Erwin
(Georgetown, KY) |
Assignee: |
Lexmark International, Inc.
(Lexington, KY)
|
Family
ID: |
41725670 |
Appl.
No.: |
12/200,156 |
Filed: |
August 28, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20100054827 A1 |
Mar 4, 2010 |
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Current U.S.
Class: |
399/329 |
Current CPC
Class: |
G03G
15/2064 (20130101); G03G 2215/00151 (20130101) |
Current International
Class: |
G03G
15/20 (20060101) |
Field of
Search: |
;399/328,329,330,320,122 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gray; David
Assistant Examiner: Lactaoen; Billy J
Claims
What is claimed is:
1. A fuser for an image forming machine, comprising: an endless
belt having opposite marginal side edge portions and opposite
exterior and interior surfaces on said belt extending between said
opposite marginal side edge portions; a heater housing disposed
within said endless belt such that said interior surface thereof
surrounds said housing lengthwise between opposite ends of said
housing; a pair of end caps mounted to opposite ends of said
housing adjacent to opposite lateral sides of said belt, each of
said end caps having an inner flange spaced radially outward from a
center portion of said end cap and radially inward from said
opposite marginal side edge portions of said belt so as to define a
clearance with radial height between said inner flange and said one
of said opposite marginal side edge portions of said endless belt;
and a plurality of protuberances defined on said inner flange of
each of said end caps projecting toward said one of said opposite
marginal edge portions of said endless belt and circumferentially
spaced apart from each other to reduce belt skew relative to said
end caps by enabling at least one of decreasing the surface area of
contact of said inner flange of said end cap with said one of said
opposite marginal side edge portions of said endless belt to the
reduced surface areas of contact of said protuberances with said
one of said opposite marginal side edge portions of said belt and
decreasing the radial height of the clearance between said inner
flange and said one of said opposite side edge portions of said
belt to the reduced radial height between said one marginal side
edge portion of said belt and said protuberances.
2. The fuser of claim 1 wherein the profile of said protuberances
of each of said end caps in their respective shapes and numbers
when taken together are tailored to conform to the shape of said
one of said opposite marginal side edge portions of said belt so as
to reduce the surface area of said inner flange that comes in
contact with said belt.
3. The fuser of claim 1 wherein the profile of said protuberances
of each of said end caps in their respective circumferential and
radial positions when taken together are tailored to conform to the
shape of said one of said opposite marginal side edge portions of
said belt so as to reduce the surface area of said inner flange
that comes in contact with said belt.
4. The fuser of claim 1 wherein at least some of said protuberances
are at different heights from said inner flange of said end
cap.
5. The fuser of claim 1 wherein all of said protuberances are at
different radial heights from said inner flange of said end
cap.
6. The fuser of claim 1 wherein said protuberances project
outwardly from said inner flange along radial lines extending
substantially from said central portion of said end cap.
7. The fuser of claim 1 wherein said protuberances are integrally
molded in said inner flange of said end cap.
8. The fuser of claim 1 wherein said protuberances are made from
one of a plastic or metal material attached to said end cap.
9. A fuser for an image forming machine, comprising: an endless
belt having opposite marginal side edge portions and opposite
exterior and interior surfaces on said belt extending between said
opposite marginal side edge portions; a backup pressure roll
disposed along a portion of said endless belt and making rotational
contact therewith so as to cause rotation of said endless belt and
form a nip therewith having an entrance and an exit; a heater
housing disposed within said endless belt such that said interior
surface thereof surrounds said housing lengthwise between opposite
ends of said housing and as said endless belt is rotated about said
housing; a pair of end caps mounted to opposite ends of said
housing adjacent to opposite lateral sides of said belt, each of
said end caps having an inner flange spaced radially outward from a
center portion of said end cap and radially inward from said
opposite marginal side edge portions of said belt so as to define a
clearance with radial height between said inner flange and said one
of said opposite marginal side edge portions of said endless belt
as said belt rotates relative to said end caps; and a plurality of
protuberances defined on said inner flange of each of said end caps
projecting toward said one of said opposite marginal edge portions
of said endless belt and circumferentially spaced apart from each
other to reduce belt skew relative to said end caps by enabling at
least one of decreasing the surface area of contact of said inner
flange of said end cap with said one of said opposite marginal side
edge portions of said endless belt to the reduced surface areas of
contact of said protuberances with said one of said opposite
marginal side edge portions of said belt and decreasing the radial
height of the clearance between said inner flange and said one of
said opposite side edge portions of said belt to the reduced radial
height between said one marginal side edge portion of said belt and
said protuberances.
10. The fuser of claim 9 wherein said clearance is less nearer to
the location of said entrance to said nip than when nearer to the
location of said exit from the said nip such that the radial
projections of said protuberances nearer to the location of said
entrance are less than when nearer to the location of said exit and
in such manner the profile of said protuberances when taken
together are thereby tailored to correspond to the width of said
clearance at said locations.
11. The fuser of claim 10 wherein said protuberances going from
said entrance to said exit of said nip increase in radial height
from said inner flange as the radial height of said clearance
between said belt and said inner flange increases.
12. The fuser of claim 9 wherein the profile of said protuberances
of each of said end caps in their respective shapes and numbers
when taken together are tailored to conform to the shape of said
one of said opposite marginal side edge portions of said belt so as
to reduce the surface area of said inner flange that comes in
contact with said belt.
13. The fuser of claim 9 wherein the profile of said protuberances
of each of said end caps in their respective circumferential and
radial positions when taken together are tailored to conform to the
shape of said one of said opposite marginal side edge portions of
said belt so as to reduce the surface area of said inner flange
that comes in contact with said belt.
14. The fuser of claim 9 wherein at least some of said
protuberances are at different radial heights from said inner
flange of said end cap.
15. The fuser of claim 9 wherein all of said protuberances are at
different radial heights from said inner flange of said end
cap.
16. The fuser of claim 9 wherein said protuberances project
outwardly from said inner flange along radial lines extending
substantially from said central portion of said end cap.
17. The fuser of claim 9 wherein said protuberances are integrally
molded in said inner flange of said end cap.
18. The fuser of claim 9 wherein said protuberances are made from
one of a plastic or metal material attached to said end cap.
19. The fuser of claim 1 wherein said clearance is less nearer to
the location of an entrance to a nip of said fuser than when nearer
to the location of an exit from the said nip such that the radial
projections of said protuberances nearer to the location of said
entrance are less than when nearer to the location of said exit and
in such manner the profile of said protuberances when taken
together are thereby tailored to correspond to the width of said
clearance at said locations.
20. The fuser of claim 19 wherein said protuberances going from
said entrance to said exit of said nip increase in radial height
from said inner flange as the radial height of said clearance
between said belt and said inner flange increases.
Description
BACKGROUND
1. Field of the Invention
The present invention relates generally to image forming machines
and, more particularly, to a fuser for an image forming machine
with end caps having protuberances strategically placed on an inner
flange for reducing belt skew.
2. Description of the Related Art
An image forming machine, such as a printer, copier, fax machine,
all-in-one device or a multifunctional device, typically includes a
heating device, such as a fuser, to fix a developing agent, such as
toner, to a media sheet. The fuser typically contains a heater and
an endless belt and backup pressure roll that form a nip for the
media sheet to pass through. They provide heat and/or pressure to
the toner to soften the toner so that it will adhere to the media
sheet. The fuser belt defines an inner loop. The heater is
positioned within the inner loop and in direct contact with the
belt. The heater has a profile generally corresponding to the
travel path of the belt to provide an area contact rather than a
line contact for more efficient thermal transfer. The heater is in
the form of a ceramic heater held in a heater housing positioned
within the inner loop and against the belt. The fuser belt is an
"idling belt" having no drive rolls within it. The belt is driven
by the rotation of the backup pressure roll, through the driving
association of the belt with the pressure roll at the nip.
The location of the belt is controlled by an end cap attached to
each end of the heater housing. The end cap has an inner flange
that limits the left to right axial movement of the belt. The
backup pressure roll rotates which, in turn, rotates the belt and
drives the print media through the fuser nip. The end caps do not
rotate.
Sometimes the belt in the fuser skews with respect to the fuser
backup pressure roll and the end caps. The belt skew results from
differences in friction along the heater. This misalignment allows
the belt to infringe on the media path as it enters the fuser nip
causing smudging on the printed page that results in unacceptable
print quality. Another phenomenon that belt skew affects is the
"left to right" movement of the media as it passes through the
fuser nip. This is known as "media walk" and is defined as the
distance in millimeters the paper moves side to side. Excessive
media walk may cause the media to crash into limiting features
within the printer's paper path.
Thus, there is still a need for an innovation that will reduce skew
between the end caps and the belt so as to reduce belt skew with
the backup pressure roll.
SUMMARY OF THE INVENTION
The present invention meets this need by providing an innovation
that strategically places features in the form of protuberances on
the inner flange of each of the end caps that reduce the amount of
belt skew by reducing the clearance between the inner flange of the
end cap and the belt and also reducing the area of surface contact
between the inner flange and the belt.
Accordingly, in an aspect of the present invention, a fuser for an
image forming machine includes an endless belt having opposite
marginal side edge portions and opposite exterior and interior
surfaces on the belt extending between the opposite marginal side
edge portions, a heater housing disposed within the endless belt
such that the interior surface thereof surrounds the housing
lengthwise between opposite ends of the housing, a pair of end caps
mounted to opposite ends of the housing adjacent to opposite
lateral sides of the belt, each of the end caps having an inner
flange spaced radially outward from a center portion of the end cap
and radially inward from the opposite marginal side edge portions
of the belt so as to define a clearance of a first radial width
between the inner flange and the one of the opposite marginal side
edge portions of the endless belt, and a plurality of protuberances
defined on the inner flange of each of the end caps projecting
toward the one of the opposite marginal edge portions of the
endless belt and circumferentially spaced apart from each other to
reduce belt skew relative to the end caps by enabling at least one
of: decreasing the surface area of contact of the inner flange of
the end cap with the one of the opposite marginal side edge portion
of the endless belt to the reduced surface area of contact of the
protuberances with the one of the opposite marginal side edge
portions of the belt or decreasing the radial height of clearance
between the inner flange and the one of the opposite side edge
portions of the belt to the reduced radial height between the one
marginal side edge portion of the belt and the protuberances.
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus described the invention in general terms, reference
will now be made to the accompanying drawings, which are not
necessarily drawn to scale, and wherein:
FIG. 1 is a schematic end view of an exemplary embodiment of a
fuser of an image forming machine with a media sheet having toner
thereon traveling through a nip between an endless belt and a
backup pressure roll of the fuser.
FIG. 1A is an enlarged fragmentary sectional view of an end cap of
the fuser as seen along line 1A-1A of FIG. 1 showing inner and
outer flanges of the end cap and a marginal side edge portion of an
endless belt of the fuser extending into the clearance between the
flanges and containing no feature.
FIG. 2 is a schematic side elevational view of the belt showing the
angle of belt skew at approximately 1.degree..
FIG. 3 is an enlarged schematic end view of the belt showing too
much contact of the inner flange of the end cap with the belt,
resulting in high friction in small local areas of the belt which
produces adverse effects on the belt.
FIG. 4 is a view of the belt similar to that of FIG. 3 but now
showing the inner flange of the end cap having features of the
present invention strategically located or place on the inner
flange about the clearance between it and the belt.
FIG. 4A is a view of the end cap similar to that of FIG. 1A now
showing a feature or protuberance separately provided on the inner
flange and underlying the marginal side edge portion of the endless
belt.
FIG. 4B is a view similar to that of FIG. 4A but now showing a
feature or protuberance integrally formed on the inner flange and
underlying the marginal side edge portion of the endless belt.
FIG. 5 is a view of the belt similar to that of FIG. 2 but now
showing the angle of belt skew reduced to approximately
0.1.degree..
FIG. 6 is a bar graph of the angle of belt skew with and without
features of the present invention.
FIG. 7 is a bar graph of the amount of media walk per page with and
without the features of the present invention.
DETAILED DESCRIPTION
The present invention now will be described more fully hereinafter
with reference to the accompanying drawings, in which some, but not
all embodiments of the invention are shown. Indeed, the invention
may be embodied in many different forms and should not be construed
as limited to the embodiments set forth herein; rather, these
embodiments are provided so that this disclosure will satisfy
applicable legal requirements. Like numerals refer to like elements
throughout the views.
Referring now to FIG. 1, there is illustrated an exemplary
embodiment of a fuser, generally designated 10, of an image forming
machine (not shown). The fuser 10 fixes or fuses toner particles 12
defining an image to a media sheet 14. Toner particles 12 may be
monochrome particles or particles of different colors (e.g., cyan,
magenta, yellow and/or black particles). The fuser 10 includes an
endless belt 16, a heater 18 and a backup pressure roll 20. The
belt 16 defines an inner loop 22 having a metal tube and, to
improve the degree to which the belt conforms to the varying
heights of the various piles of toner particles, a compliant rubber
layer on the base and a release coating covering the rubber layer
to enhance thermal conductivity. More specifically, the belt 16 is
typically a Teflon.RTM. coated, silicone rubber molded over a
flexible metal tube.
The heater 18 is positioned within the inner loop 22 and in direct
contact with the endless belt 16. The heater 18 has a profile
(e.g., flat or curved) generally corresponding to the travel path
of the belt 16 to provide an area contact rather than a line
contact for more efficient thermal transfer. The heater 18 may be
in the form of a ceramic heater component held in a heater housing
24 positioned within the inner loop 22 of and against the belt 16.
The belt 16 is somewhat loosely fit around the heater housing 24,
which is a high-temperature plastic body made of a liquid crystal
polymer, in one example about 22% glass and mineral filled but not
limited to this combination.
The backup pressure roll 20 defines a nip 26 with the belt 16
through which the print media sheet 14 travels. The nip 26 has an
entrance 26A and an exit 26B. The belt 16 is positioned adjacent
the toner side 14A of the sheet 14 as it is transported through the
nip 26, with the pressure roll 20 on the opposite side thereof. As
known to those skilled in the art, the backup pressure roll 20
includes a metal core 28, a compliant layer 30 surrounding the core
28, and a release layer 32 surrounding the compliant layer 30. The
metal core 28 may be formed from a suitable metal that provides
structural rigidity and stores thermal energy, such as extruded
aluminum or steel. The compliant layer 30 may be formed from a
material providing compliance of pressure roll 20, and can be in
the form of silicone rubber, but may be formed of other resilient
materials. Additionally, the release layer 32 may be in the form of
a sleeve made from a material providing suitable release
properties.
The endless belt 16 is a so-called "idling belt" having no drive
rolls within its inner loop 22. The belt 16 is driven by the
rotation of the backup pressure roll 20 through the driving
association of the belt 16 therewith in the nip 26. The print media
sheet 14 is transported to the fuser 10 by a transport belt (not
shown), and passes through the nip 26. During printing, the fuser
10 fixes or fuses the toner particles 12 to the toner side 14A of
the print media sheet 14. The heater 18 positioned within the inner
loop 22 of the endless belt 16 is energized such that the heater 18
provides a desired heat output. Heat is transferred principally via
conduction from the heater 18, through the belt 16, and to the
outer periphery of the backup pressure roll 20. The outer surface
16A of the belt 16 is also the surface that transfers heat to toner
particles 12, for fixing or fusing an image on the print media
sheet 14. The print media sheet 14 is transported through the nip
26 between the backup pressure roll 20 and the belt 16. Heat is
transferred from the belt 16 to toner particles 12, to fix or fuse
the image on the sheet 14, and is additionally transferred to the
backside of the sheet 14 from the pressure roll 20, to assist in
the fusing process. The compliant rubber layer of the belt 16
accommodates the varying thickness of toner particles 12 on the
print media sheet 14.
The fuser 10 also includes end caps 34 (one being shown at the one
end of the fuser 10 shown in FIGS. 1, 3 and 4 and fragmentarily
shown in FIGS. 1A and 4A) attached to opposite ends 24A of the
heater housing 24 and by which means the side-to-side location of
the belt 16 is controlled. Each end cap 34 has a substantially
circular inner flange 36 that fits inside of the inner loop 22, the
inside diameter, of the belt 16 with an outer surface 36A of the
inner flange 36 to locate the belt 16 up and down and front to back
in the fuser 10. The outer surface 36A of the inner flange 36 of
the end cap 34 is shaped to match the shape or configuration the
belt 16 (as viewed from an end as seen in FIGS. 1, 3 and 4) wants
to take when the belt 16 is pressed up against the heater 18 by the
backup pressure roll 20. The inner flange 36 of the end cap 34
limits the left to right axial movement of the belt 16. The end cap
34 also has an outer flange 38. As best seen in FIGS. 1A and 4A,
both inner and outer flanges 36, 38 project in the same direction
from an end panel 40 of the end cap and a clearance 42 is defined
between the inner and outer flanges 36, 38 due to their being
spaced apart radially from one another. As mentioned above, the
endless belt 16 is an idler; it is only rotated due to the pressure
and angular forces applied to it by the rotation of the backup
pressure roll 20 in driving the print media sheet 14 through the
fuser nip 26. The end caps 34 do not rotate.
As seen in FIG. 2, heretofore it has been noted that the belt 16,
and thus its central axis 44 (see also FIG. 4) in the fuser 10 can
skew with respect to the rotational axis 46 of the backup pressure
roll 20 and to the end caps 34. Belt skew is believed to result
from differences in friction between the heater 18 and belt 16
along the length of the heater 18. The angle of the belt skew
relative to the axis 46 of the backup roll 20 can be up to
approximately 1.degree.. Though this degree of belt skew may seem
slight it can have large consequences. This misalignment allows the
belt 16 to infringe on the media path as it enters the fuser nip 26
at entrance 26A causing smudging on the printed sheet 14 that
results in unacceptable print quality. Another phenomenon that belt
skew affects is the "left to right" movement of the media sheet 14
as it passes through the fuser nip 26. This is known as "media
walk" and is defined as the distance in millimeters the sheet 14
moves side to side. Excessive media walk may cause the media to
crash into limiting features within the printer's paper path.
When too much of the surface of the inner flange 36 comes in
contact with the belt 16, as depicted in FIG. 3, this condition
could cause what is termed "Band Brake" effect. This would result
in high friction in very small local areas of the belt 16. In this
case two phenomenons could occur. The first is that the increased
friction would cause the belt 16 to stop momentarily. This stoppage
would result in a print quality defect on the print page. The
second would be catastrophic belt failure or destruction due to
extremely high torque placed on the belt 16. This would render the
printer inoperative.
To minimize friction with the inner surface 16B of the belt 16 a
portion of the clearance 42 provided between the inner and outer
flanges 36, 38 is also between the inner surface 16B of one of the
opposite marginal edge portions 16C of the belt 16 and the outer
surface 36A of the inner flange 36, as seen in FIG. 1A. It should
be noted that the clearance 42 between the inner and outer flanges
36, 38 of the end cap 34 and the marginal side edge portions 16C of
the metal belt 16 is important to the performance of the fuser 10
when it is a color fuser. The amount of the clearance 42,
side-to-side, is what allows the belt 16 to skew. This clearance 42
allows the belt central axis 44 to not be parallel to the backup
roll axis of rotation 46. The relative angle between these axes 44,
46 creates a point load at the contact point of the belt 16 and the
end cap 34. In addition to accelerated wear due to this point load,
another failure mode is caused by this point load. This point load
can produce a localized buckling of the belt 16 as it contacts the
end cap 34. This buckling usually results in the belt 16 bending
over short distances. Since it is localized the buckling fatigues
the edge of the belt 16 and can put a crease in the belt 16.
Buckling results in fatigue of the belt 16 which results in cracks
in the belt 16 in the axial direction and circumferential
direction. These cracks cause failure of the belt 16.
The present invention is directed to features provided on the inner
flange 36 of the end cap 34 which reduce the amount of belt skew by
taking up or reducing portions of the clearance 42 that exists
between the opposite marginal side edge portions 16C of the endless
belt 16 and the inner flanges 36 of the end cap 34. In an exemplary
embodiment as seen in FIGS. 4 and 4A, these features take the form
of a plurality of dimples or protuberances 48A-48D formed on the
inner flange 36 of the end cap 34 which are circumferentially
spaced from one another and project outward along radial lines
50A-50B from a central portion 52 of the end cap 34. The profile of
the number and shapes of protuberances 48A-48D and their
circumferential and radial positions when taken together and also
their total surface contact areas may be tailored so as to conform
to the profile of the path of travel of the endless belt 16 and
reduce the radial height of the clearance 42 between the inner
flange 36 and the belt 16 and the amount of the surface area of the
inner flange 36 to come in contact with the belt 16. Thus the
spacing or distance between the protuberances 48A-48D is important
so that the "Band Brake" phenomenon does not occur because of too
much frictional contact, as also shown and described in FIG. 3.
In FIGS. 4A and 4B, there is shown the protuberances 48A-48D
provided in alternative designs in the inner flange 36 with respect
to how they reduce the radial height of the clearance 42 between
the inner flange 36 of the end cap 34 and the inside of the metal
belt 16. These features or protuberances 48A-48D are strategically
positioned circumferentially around the inner flange 36 of the end
cap 34, as best seem in FIG. 4, where the radius of the belt 16 is
closest to the natural radius of the belt 16 under zero loading so
that no additional stresses are imposed on the metal belt 16.
Because the clearance portion 42A is lesser at locations nearer the
entrance 26A to the nip 26 than at locations nearer the exit 26B
from the nip 26, which in part at least may be due to the fact that
the direction of the pulling force exerted on the belt 16 goes from
the entrance 26A toward the exit 26B of the nip 26, the radial
projection beyond the inner flange 36 of the one of the
protuberances 48A-48D, as viewed along radial lines 50A-50D, nearer
to the entrance 26A may be less than the radial projection beyond
the inner flange 36 of the one of the protuberances 48A-48D nearer
to the exit 26B. Also, the protuberances 48A-48D going from the
entrance 26A to the exit 26B may increase in radial height as the
height of the clearance 42 between the belt 16 and inner flange 36
increases. In such manner, the profile of the protuberances 48A-48D
when taken together are tailored to correspond to the height of the
clearance 42 at these locations and to the profile of the path of
travel of the endless belt 16. The protuberances 48A-48D can be
features integrally molded, as seen in FIG. 4B, on the inner flange
36 of the end cap 34 or features separately provided, as seen in
FIG. 4A, on an insert made from plastic or metal material that is
attached to the end cap 34, such as between the end panel 40 and
the inner flange 36.
To recap, the present invention is directed to features taking the
form of dimples, protrusions or bulges, referred to generically as
protuberances 48A-48D, on the inner flange 36 of the end cap 34
that control belt skew. Thus, point loads of the belt 16 on the end
cap 34, due to the angle .theta..sub.t between the belt 16 and end
cap 34 as depicted in FIGS. 3 and 4, or run-out of the belt 16 can
be compensated for resulting in elimination of belt end flaring and
thus damage. These features control the front to back axial motion
of the belt 16 and reduce the amount of media sheet walk rate which
can cause the media sheets 14 to crash into limiting features
within the printer's paper path. Improved control of belt skew with
the implementation of protuberances 48A-48D compared to the
situation without them is clearly illustrated in FIG. 5 and in the
bar graph of FIG. 6 which show that the angle of belt skew is
reduced to approximately 0.1.degree. The improved media walk rate
is shown in the bar graph of FIG. 7.
The foregoing description of several embodiments of the invention
has been presented for purposes of illustration. It is not intended
to be exhaustive or to limit the invention to the precise forms
disclosed, and obviously many modifications and variations are
possible in light of the above teaching. It is intended that the
scope of the invention be defined by the claims appended
hereto.
* * * * *